


Big Sis Loves Me

by Azenguin



Category: OMORI (Video Game)
Genre: Bad Touch, Bad Touch Mari, Dildos, F/F, Grooming, Incest, POV First Person, Sibling Incest, Trans, Trans Female Character
Language: English
Status: Completed
Published: 2021-03-07
Updated: 2021-03-07
Packaged: 2021-03-13 00:36:09
Rating: Explicit
Warnings: Rape/Non-Con, Underage
Chapters: 1
Words: 1,409
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29892981
Author URL: https://archiveofourown.org/users/Azenguin/pseuds/Azenguin
Summary: This is a very self indulgent fic involving Mari teaching Sunny how to be a girl, as well as any other shenanigans with her sister. Read the warnings and tags before touching this.
Relationships: Mari/Sunny (OMORI)
Comments: 10
Kudos: 24





	Big Sis Loves Me

“I…I want to be a good girl... “ I pant out through labored breaths, staring at my computer, my left hand… occupied with things. Using my free hand, I click through my bookmarks, settling on my favorite. A cute boy, upon being discovered by her sibling, slowly gets forced to dress, talk, and act like a girl. Scrolling through the story, I involuntarily moan from the pleasure building in my… thing, as well as from the pinching pain in my nipple… “Wait, how-” I barely manage to stammer out before looking back. Standing there is Mari, smiling and looking at me as if I wasn’t just masturbating in front of her. “I-it’s not wh-”

“Shhh, Sunny. It’s ok. I won’t tell anyone” she coos to me, putting her finger up to my mouth. _Oh my god… I’m the luckiest girl alive… be calm, Mari, be calm._ “You know, I saw what you were reading and,” my breath hitches slightly at her words “I wanted to tell you it’s nothing to be ashamed of”

Speechless, I look up at her wide-eyed, not knowing how to possibly respond. Stammering, I eke out a response “I.. but you… just saw me…”

“I know, but really, it’s kinda cute. You know, I always did want a sister” she assures me, smiling warmly. I know then and there that I could never ask for a better sister. She’s so selfless… she doesn’t even seem remotely upset. I return her smile, mewling as I whimper out a small “...thank you”, before I cling to her, forgetting all about my state of undress.

_Oh my god I can’t believe it. That really worked… now I’ve got her right where I want her_

* * *

It’s been a few days since then. Mari and I have been as close as we always have been, but this has still been nagging me even to today. I went downstairs, only to find Mari reading a note. Apparently, mom’s going away on a business trip for a while. Luckily, I still have my big sis here.

“So, Sunny, are you feeling alright?” Mari asks me, full of genuine concern.  
  
“Ah, um… yeah. I…”

“You know you can tell me anything. I’m your big sister! There’s nothing to worry about, I promise.”  
  
...fuck it, I’m not going to get another opportunity. “Mari, I’m a girl… or well, I want to be, but if you…” I get off before Mari hugs me tightly. I tear up a bit, looking up to her for approval

“Aw, Sunny. That’s fine by me! I’ll always love you, lil sis.” as she says this, I can’t help but crack a little smile. “You know, I have some things that may be useful for you, if that’s the case. I can even help you with transitioning! Who better to help than your big sister?” 

“I… yes… that would be nice.” 

After a quick breakfast, she guides me back up to our room, smiling gently. I really do have the best big sister in the world. _Oh my god, yes! This is going to be so fun..._

* * *

“Just pull those up aaaannd… perfect!”

I can see Mari smiling at me as I pull up her… my leggings. They feel so nice and smooth, whenever she runs her hands up and down them. As I stand up, I can’t help but do a small twirl, spinning my sundress around. I feel really… happy… oh god why now? Instinctively I cover my groin up, the growing hardness feeling, somehow, far more upsetting than it has any right to be

“Sunny, it’s perfectly natural for something like that to happen, you know? It doesn’t make you weird at all. I promise.” While her words are… slightly helpful, I can’t help but still feel bad about it. I look up to her, and she smiles, as if she already knew what I was going to say. “I have a special way to fix that, you know? It’s the most feminine way possible. Though you have to keep it a secret. If you don’t, people may stop you from doing it ever again!”  
  
Upon hearing that, I get scared. Having to deal with this all the time. They might even decide to not let me be a girl… shivering, I listen thoughtfully, only saying “Please tell me” in a very quiet voice, ignoring the fact we’re alone.

Reaching under her bed, she pulls out an old shoebox. It’s so unlike her to have something like that. When she opens it, there’s a… is that a dildo? My… thing grows ever so slightly harder upon realizing that.

“Now, this is a toy that a lot of girls use to take care of things down there. They don’t have what you have down there, so I’d suggest not using it either! Although, if you want, you can rub your clit with your thumb or a finger, but judging by your expression” I suddenly became aware that I looked uncomfortable even hearing about me using it… “I doubt you’ll want to. Since this is your first time using it, just let big sis handle everything, ok?”

I slowly nod… “be gentle”

“I promise I will be~”

* * *

I wait there, laying on my back, legs spread apart. Mari let me keep my dress on… she’s so considerate of my needs. _Oh my gosh, she looks so cute like that. Her little sundress just barely covers her clit… she looks so pure and innocent…_ Suddenly, I feel a cold, slimy sensation right on my butt. I jump up slightly, shivering a bit.

“Oh Sunny, I’m so sorry. I just can’t use the dildo without making sure you can take it. It would hurt you too much otherwise, and I couldn’t do that to you!”

Nodding, I brace myself for more of that feeling. But as she applies more of that goo, her fingers start slipping in… it feels… pretty nice. I can’t help but blush a little as I watch her smiling face, as she slips the next finger in, gently pumping them inside me. It feels… I don’t know, right? Like I was always meant to do this.

As she pulls the fingers out, I whimper, out of the blue. “Don’t worry. Something else will replace that soon” she tells me, rubbing my head with her (thankfully non-lubed) hand. The dildo looks intimidating. It’s not particularly large, or threatening… it’s even a bright pink. It kinda reminds me of Aubrey, since that always was her favorite color… it just… I shake my head. I want to do this. I know I do. I try to give my best smile, but she still reassures me, “Don’t worry, I’ll be gentle. This is your first time after all, I wouldn’t want it to hurt”

It slides into me, and I can feel my body tensing against it. It hurts slightly but… it’s starting to feel good… even better than the fingers. My breathing gets heavier, as my… my clit, starts to get wet. Upon seeing this, I hear her gushing about how I got wet, just like a girl. My mind is racing already. I can’t really understand any of the words she’s saying to me. I just start remembering my favorite stories. The trance is broken as she hits up against something, and I feel so… so good from it. I immediately plead “Please, do that more!”

She smiles at me “You feel that, that’s a place where girls like you can feel good, just like any other girl.” After saying that, she smiles, before thrusting the dildo even faster inside me… I can’t help but to reach under my dress and twist my nipples. I can barely even see what’s going on anymore, it just… feels so good.

_This feels so good… she looks so adorable spread out like this. And she’s just letting me do it… I feel like I’m about to burst at the seams_

“Please Mari.. please… just a little…” I get out, before my clit sprays out all over Mari. I can’t even get concerned, since I’m too in a daze to care anymore. As she removes the dildo with an audible plop, I let out a small moan, as the last remnants of conscious thought leave me, Mari joins me in bed. She’s a bit wet and sticky, especially on her own groin, but it doesn’t matter, we can wash up after a… nap…

**Author's Note:**

> This is my first fic I felt I could publish, so I do hope you enjoyed. If you liked it, I'm really glad, and I hope you have a fantastic day. Please enjoy yourselves. If you came here to spread hate, that's only going to make me feel more driven to make works like this, and even more chapters for it. Regardless, enjoy you lovely lovely people


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